Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 8: Being Normal: Normalization and Other Basic Design Issues
This will essentially evaluate each character that the user is trying to enter in the PartNo column of our
table. The first character will have to be 0 through 9 , the second A through Z (an alpha), and the next
four will again have to be numeric digits (the 0 through 9 thing again). We just enter this into the text
box labeled Expression. In addition, we’re going to change the default name for our constraint from
CK_Products to CKPartNo, as shown in Figure 8-33.
That didn’t take us too long — and we now have our first database that we designed!!!
This was, of course, a relatively simple model — but we’ve now done the things that make up perhaps
90 percent or more of the actual data architecture.
Summary
Figure 8-33
Database design is a huge concept, and one that has many excellent books dedicated to it as their sole
subject. It is essentially impossible to get across every database design notion in just a chapter or two.
In this chapter, I have, however, gotten you off to a solid start. We’ve seen that data is considered normalized
when we take it out to the third normal form. At that level, repetitive information has been
eliminated and our data is entirely dependent on our key — in short, the data is dependent on: “The key,
the whole key, and nothing but the key.” We’ve seen that normalization is, however, not always the right
answer — strategic de-normalization of our data can simplify the database for users and speed reporting
performance. Finally, we’ve looked at some non-normalization related concepts in our database design,
plus how to make use of the built-in diagramming tools to design our database.
In our next chapter, we will be taking a very close look at how SQL Server stores information and how to
make the best use of indexes.
259